|Title|Author|Date|Length (first edition)|
|---|---|---|---|
|Bull-Dog Drummond|H. C. McNeile|1920|320 pp|
|The Black Gang|H. C. McNeile|1922|318 pp|
|The Third Round|H. C. McNeile|1924|320 pp|
|The Final Count|H. C. McNeile|1926|319 pp|
|The Female of the Species|H. C. McNeile|1928|312 pp|
|Temple Tower|H. C. McNeile|1929|320 pp|
|The Return of Bulldog Drummond|H. C. McNeile|1932|316 pp|
|Knock-Out|H. C. McNeile|1933|317 pp|
|Bulldog Drummond at Bay|H. C. McNeile|1935|310 pp|
|Challenge|H. C. McNeile|1937|311 pp|
|Bulldog Drummond on Dartmoor|Gerard Fairlie|1938|254 pp|
|Bulldog Drummond Attacks|Gerard Fairlie|1939|287 pp|
|Captain Bulldog Drummond|Gerard Fairlie|1945|256 pp|
|Bulldog Drummond Stands Fast|Gerard Fairlie|1947|319 pp|
|Hands Off Bulldog Drummond|Gerard Fairlie|1949|271 pp|
|Calling Bulldog Drummond|Gerard Fairlie|1951|255 pp|
|The Return of the Black Gang|Gerard Fairlie|1954|192 pp|
|Deadlier Than the Male|Henry Reymond|1967|192 pp|
|Some Girls Do|Henry Reymond|1969|192 pp|

Question: what year was the earliest bull-dog drummond published?
Answer: 1920